Sheath



FIG. 1 is a side elevational view of a sheath according to the invention;

FIG. 2 is a top plan view thereof, a knife handle is shown in dotted lines for environmental purposes and forms no part of the claimed design;

FIG. 3 is a side elevational view thereof opposite the side of FIG. 1;

FIG. 4 is a bottom plan thereof;

FIG. 5 is an end view thereof as viewed from the left end looking toward the right of FIGS. 1-4; and,

FIG. 6 is an end view thereof as viewed from the right end looking toward the left of FIGS. 1-4.

The broken lines in FIGS. 5 and 6 depict portions of the sheath that form no part of the claimed design. 

The ornamental design for a sheath, as shown and described. 